Fix #920: Correct return-type lifting for exported methods
Implement StringBuilder.append(char[], ...) methods
Add toURI method to VirtualFiles
Merge pull request #921 from gzm0/fix-export-type-lifting

Fix #920: Correct return-type lifting for exported methods
Merge pull request #922 from gzm0/improve-string-builder

Implement StringBuilder.append(char[], ...) methods
Merge pull request #923 from gzm0/virtualfile-uri

Add toURI method to VirtualFiles